Wind power systems can have a number of environmental impacts. Large installations may be visually intrusive and there are also the concerns of associated noise, vibration, interference with telecommunications and weather, and the risk of accidents.
Farmers in the central Indian state of Maharashtra forced an inquiry after claims the 1,700 windmills in the region have contributed to a drought by chasing away the monsoon rains. One theory is that the blades' magnetic pressure draws in clouds only to "slash through" and "fragment them" before driving them away.
Low-frequency "ghostly" noise, felt through the vibrations of huge rotating propellers, has been blamed for causing headaches and depression among people living close to an on-shore wind farm at Padstow, in Cornwall, UK. Concerns are also felt for the effect of low-frequency noise on marine life, which could be significant in future given the projected surge in off-shore projects.
In 2003, the dismembered body of a red kite – one of Britain's rarest birds – was found near a wind farm in Wales. A post-mortem found the injuries were consistent with being cut by a wind turbine blade. It is claimed that turbines have killed birds in large numbers.
The UK Ministry of Defence is the biggest objector to new wind power projects on the grounds that radar operators may mistake aircraft for turbines, and vice versa. It is also considered that Turbines create "clutter" that obscures planes in the vicinity and, according to aviation authorities, compromises safety.
One of the strongest objections has been how wind farms deface rural landscapes. There are now 87 wind farms in Britain, with 1,103 turbines, each reaching up to 80 metres to the sky. Intense campaigns are being fought to oppose new wind farms on moor lands in the north west of the country, among other places. This is controversial as many people say they like the look of wind farms. The push for off-shore sites – where wind is stronger anyway – has taken some of the sting out of this. The new farms will be about five miles off shore.
Wind farms are not economic. It is only government subsidies that motivate industry to set up wind farms.
With huge off-shore wind farms planned for many coastlines, it is only a matter of time before a ship crashes into one. Why the maritime industry had been frozen out of consultations on where new wind farms should be built?
Turbines are mapped, fitted with fog horns and lights and located on sandbanks, where skippers already navigate a careful route. Engineers are working on a technical solution that will filter out moving turbines just as radar now ignores office blocks.
The British Wind Energy Association (BWEA) says rainfall marginally increased downwind of tall buildings. In addition, taking energy out of the wind increases precipitation.
In 20 years of wind power, there have been no medical conditions arising from normal operation.
Windmills in the coastal zone promote the natural growth of mini reefs which draw in more aquatic life.
The Royal Society for the Protection of Birds backs wind farms but says they must be sensibly located. Supporters also point to the long-term environmental benefits of turbines in helping to preserve breeding and foraging grounds.